Add images to readmes

[jeffpaul]

Description of the Change

This adds a screenshot of the Ollama settings page to display on the WPORG plugin page as well as the plugin banner at the top of the GH readme and the same screenshot reference therein.

Copilot summary

This pull request updates the documentation to enhance the visual presentation and clarity for users configuring the Ollama AI provider. The most important changes include the addition of new images and a screenshots section to both README.md and readme.txt, helping users better understand the plugin's configuration interface.

Documentation improvements:

• Added a banner image at the top of README.md to improve visual branding.
• Inserted a configuration screenshot into README.md to illustrate the "Settings > Ollama" screen, showing available AI models and host URL configuration.
• Added a "Screenshots" section to readme.txt, including a description of the settings screen for better clarity in the WordPress plugin directory.

How to test the Change

Changelog Entry

n/a

Credits

Props @jeffpaul.

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.